bra vs skivvies

bra

noun
  • An item of underwear worn to support the breasts. 

  • One of the two vectors in the standard notation for describing quantum states in quantum mechanics, the row vector; the other (column) vector being its complex conjugate, the ket. 

skivvies

noun
  • Underwear, particularly men′s underwear. 

How often have the words bra and skivvies occurred in a corpus of books? (source: Google Ngram Viewer )